A social-networking system, such as a social-networking website, may enable its users to interact with it and with each other through it. The social-networking system may create and store a record (such as a user profile) associated with the user. The user profile may include demographic information on the user, communication-channel information for the user, and personal interests of the user. The social-networking system may also create and store a record of the user's relationships with other users in the social-networking system (e.g. a social graph), as well as provide social-networking services (e.g. wall-posts, photo-sharing, or instant-messaging) to facilitate social interaction between or among users in the social-networking system.
Quick Response (QR) code is a type of two-dimensional barcode. A character string (e.g., text, a Uniform Resource Locator (URL), a phone number, an address, and so on) can be encoded into a QR code. A copy of a QR code can be printed out and displayed in any suitable visual display (e.g., in a magazine page, on a bulletin board, on a package of a product, and so on). A copy of a QR code can also be displayed electronically, such as in a web page or an electronic concert ticket. A user of a device capable of capturing images (e.g., a camera phone) can use the device to scan a QR code. An application hosted by the device can decode the scanned QR code, and launch an action based on the character string decoded from the scanned QR code. For example, a user can use his smart phone to scan a QR code encoding a URL link. The smart phone than can bring up in its display a web page corresponding to the URL link.